


you don't know ( you're beautiful )

by cinnabun



Category: Undertale (Video Game)
Genre: F/M, M/M, Other, PWP, Smut, Underfell, kind of, more at 11, sad bot loves local gf
Language: English
Status: Completed
Published: 2018-03-23
Updated: 2018-03-23
Packaged: 2019-04-07 03:16:16
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,497
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14071731
Author URL: https://archiveofourown.org/users/cinnabun/pseuds/cinnabun
Summary: A sequel to "anything that is beautiful (people want to break)." Mettaton shows you just how beautiful he thinks you really are.(1.5K One-Shot "Sequel" Commission - Underfell!Mettaton/Reader: Sexy Times)





	you don't know ( you're beautiful )

**Author's Note:**

  * Inspired by [anything that is beautiful (people want to break)](https://archiveofourown.org/works/13115181) by [cinnabun](https://archiveofourown.org/users/cinnabun/pseuds/cinnabun). 



* * *

 ❤ ❤ ❤

* * *

 It was getting tough not to make noise, especially with one of Mettaton’s hands buried between your legs.

When he finally leaned back from your kiss, you locked gazes. The look in his eyes sent a shiver down your spine. His eyes seemed to pulsate with lust, waves of red and gold flickering around the white, heart-shaped pupils. Tauntingly, his tongue swept over the surface of his fangs. You couldn’t help but clench your legs together.

He was so beautiful.

When he mirrored your sentiment—“You’re so beautiful, darling”—you laughed, leaning in for another kiss.

Synthetic lips pressed back to yours, hunger burning in his skin. He was so warm. Everything was so warm. His fingertips stroked the inside of your thighs, playfully edging towards that spot that you craved for him to touch so badly. Every time he seemed to be giving in, though, he’d pull back at the last second, leaving you whimpering for his attention.

“I adore you,” he whispered in your ear. “You don’t understand. To me, you are my world, my moon, & my stars. You are perfect.”

Your eyes watered. God, he was so sweet. What did you do to deserve someone who loved you so deeply? Whatever it was, you wanted to keep doing it.

He pressed against you, moving you back until you bumped against the vanity behind you. Before you could react, Mettaton was lifting you onto it, moving closer to stand between your legs. His hands pressed to the arch of your back, pulling the top half of your body flush against his.

Your neck rolled back as his kisses worked their way down. He tilted your head gently, fangs scraping against the exposed flesh. You shivered when he bit down, softly. The bite wasn’t hard enough to break skin, but you leaned into it. When he pulled back his lipstick was smudged. You giggled briefly, before he was kissing you again.

His fingers kneaded into your sides, claws threatening to rip straight through your dress. The self-control he was exhibiting was incredible because there was nothing more that you wanted than for him to rip your dress off you, right here, right now.

But you knew Mettaton wasn’t that kind of guy. He liked to take things slow, to work up to the fun part. Even if it meant you had to be left in suspense for a while. Which, in this situation, was more punishing than it usually was.

“Metta!” You whined. He just smirked, the red of your lipstick mixing with the black of his own, both smeared across the front of his teeth. “Quit teasing me.”

“How can I not?” The robot holding you cooed. For a moment his actions swept back into silly dramatics, as he wrapped both arms around you so tightly that you were pressed together, cheek-to-cheek. His skin buzzed against yours. “You’re just so adorable darling, I want to eat you up~.”

You only had a moment to process the words before Mettaton was pressing you against the surface of your vanity, his body bent at a ridiculous angle to follow you down. Dating a robot had its perks.

His hands moved up, tugging at the straps of your dress.

“Wait,” you tried to gasp, “what about the party—?”

“There’ll be other parties.” He mumbled back. “For now, let’s just celebrate being us.”

Doubt flashed in your mind. But then Mettaton swept his tongue against your lips and pulled so hard on the back of your dress that you felt something rip, and all your worries went flying out the window.

The dress hung to you in pieces. Looks like he couldn’t keep his cool after all. Not that you minded, really. While tracing gentle circles across your sides his talons flexed, tugging at the leftover ribbons, and tearing them to pieces. You watched the remains of your dress rain around you like the feathers of a pillow. Mettaton’s eyes flashed through the storm of cloth and frills.

A prickle rushed over your shoulders as you realized you were near naked, left in nothing but your underwear and a pair of stockings. But not even those were free from his playful wrath, because in a matter of moments, his hands were sweeping across bare skin, tracing across burning flesh. He squeezed your breasts gently, curling a pliant tongue around your own.

As you fidgeted needily, one of his hands returned to the hem of your panties, edging the elastic down as subtly as he could. You lifted your hips to help him shuck them off, trying not to laugh as they hung from your ankle. That humor was quickly incinerated with the fire in his gaze. There was restraint in his expression, a kind of self-control that bordered on unhinging at any given moment.

“Darling,” a soft hiss came from somewhere around his waist, and you couldn’t help but squirm in anticipation, “may I?”

“Yes,” you breathed, running your hands across his chassis. The metal shimmered under the lights, obviously dusted with a glitter of some sort that was meant to catch the party-goers eyes. Now it was like a private show, just for you. He was a rose-tinted galaxy, speckled with stars.

His eyes burned a solid gold with your next words. “Make love to me, Mettaton.”

He breathed out, slowly, and that’s when you felt it. A pressure against your entrance, prodding gently. Though you couldn’t see it from where you lay positioned, the glow was enough to sate your curiosity. A cherry red that reflected off his metal body, painting your stomach with the hue. You met his half-lidded gaze and smiled, letting your eyes slip closed when he smiled back and began to push forward.

The first few moments were tense. Your nerves screamed to panic, but you forced yourself to relax, arching to urge him onward. His hips stuttered slightly, and you felt his groan reverberate through every inch of your body. It made your bones tremble.

Then the first wave of pleasure came, and you relaxed, allowing him to take control.

His body hummed against yours, creating a delicious sensation that pulsed through your core with each movement. You let your head hang back as Mettaton shifted your hips, his talons pressing lightly over soft skin and supple flesh. Two golden beacons peered into your eyes, the colors swirling like the outer ring of a black hole. That beauty blurred as he began a slow, gentle pace.

Oh _fuck_.

Pleasure rolled through you with each slow thrust. Your eyes slipped closed when he tilted you under him, his stride increasing in speed and intensity within moments. His smirk was positively wicked.

You wriggled as his metal frame began to heat up. The fire that licked at your skin was agonizing in the best possible way. The hotter it got, the tighter the coil in your stomach became. All thoughts and instincts had melted away to one simple instinct: keep chasing that pleasure.

Bucking your hips, you bit your lip to swallow back your wails of desire. Mettaton hunched over you, his jaw hanging slack, fangs glistening. A low humming came from within him somewhere, growing louder as he quickened his movements even more.

Oh fuck, oh shit—

“Metta—Metta,” you gasped, fingers tangled in your hair. “Please don’t stop oh god, please, please, _please_ —”

The above clinging to yours jerked hard. His hips pressed as tightly to yours as either of you could muster, the shivers of his oncoming release finally snapping that winding pressure that had been building up for so long.

A cry bubbled in your throat, hardly able to escape before Mettaton was kissing you, swallowing your moans. Your bodies jerked in tandem, that white-hot fire bursting through every nerve. The heat faded as quickly as it began. Bonelessly, you slumped back against the cool wood of your vanity, heaving for air as the robot above you gasped and growled.

His golden gaze faded, that hungry look slowly replaced with a kind of reverent awe as the color in them faded back to red. Mettaton leaned down and kissed you once again. This time, however, he let that moment last, gently leaning his forehead against yours.

Maybe it was just the intimacy that was getting to you, but you were almost certain you could hear his SOUL beating in tandem with your heart.

Gently, your boyfriend lifted you from your spot, reluctant to let you go as you moved to the bed. Once comfortable amongst the sheets and blankets, he lay by your side, gazing into your eyes. You couldn’t help but smile as you caught the gold that speckled his crimson irises.

He smiled back, whispering as you drew closer to his warmth. “How do you feel, love?”

A soft, shuddering sigh worked through you. “I feel like I love you.”

His smile broadened deeply, tiny fangs still smeared with crimson and ebony lipstick.

“I love you too, darling.”

* * *

❤ ❤ ❤

* * *

 

**Author's Note:**

> i haven't had the chance to write much sin for uf!metta, so this was a fun exercise. thank you so much to my commissioner, i'm happy that i got the chance to write for you again.
> 
> with that being said, i'm still available for comms/stuff, so if ur interested hmu~.
> 
> reviews & kudos are greatly appreciated !!
> 
> \- cinnabun


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